This invention relates in general to work-holders and, more particularly, to a clamp especially adapted for welding.
Heretofore, limited efforts have been made to develop, what are sometimes referred to as, fitting-up tools for maintaining work pieces in desired relationship for reliable welding and with such tools, there has been, in general, a resort to magnetic means for interengaging the tool and the work pieces for promoting appropriate securement during operation. One such effort is disclosed in U.S. Pat. No. 2,379,136, granted June 26, 1945, which shows the use of an electromagnet connected by a cable to a suitable source of electrical energy and with threaded members or so-called jack screws on either side thereof. The device of this patent is an integrated structure. Another effort is disclosed in U.S. Pat. No. 3,593,982 which is also an integrated structure embodying at one end a U-shaped permanent magnet and with the tension member or jack screw 13 at the other end. These structures are exemplary of the prior art demonstrating an exceedingly limited range of adjustability being more or less designed for relatively specific work arrangements. Furthermore, each is devoid of what might be considered a balanced magnetic condition since with the former, the application of a strong magnetic force would tend to push the work material away from the jack screws and, thus, render uncertain the results to be obtained; while, in the latter, exertion of a relatively strong holding force by the jack screw might tend to cause the magnet to loose contact.
Therefore, it is an object of the present invention to provide a work-holder or clamp of the character stated which is comprised of a plurality of discrete components adapted for interengagement throughout a wide range of positions of adjustment for accommodating a veritable multiplicity of work piece attitudes.
It is another object of the present invention to provide a clamp of the character stated embodying simple but fully reliable means for detachably interengaging the constituents.
It is a still further object of the present invention to provide means for easily interengaging the components of the clamp without resort to tools or other extrinsic devices whereby the clamp is fully self-contained.
It is another object of the present invention to provide a clamp of the character stated embodying magnets presented in balanced relationship and which are adapted for relative rockability to assure effective securement to uneven or irregular surfaces as well as to assure presentation of the device in fully effective condition despite any unevenness, tilting, or the like of the work pieces.
It is a still further object of the present invention to provide a clamp of the character stated which embodies a hold-down member so disposed with respect to the magnets as to prevent any untoward disengagement of the latter through application of relatively increased holding forces.
It is a further object of the present invention to provide a clamp of the character stated which comprises a plurality of simple, sturdy, and extremely durable components; which clamp may be economically produced; which may be utilized without developed skill on the part of the user; which may be effectively employed for work holding in other than welding situations; and which is reliable in use.